The Section continues to provide expert physical and technological support for radiation treatment, consisting of routine calibration and quality assurance of all radiation equipment. It includes special dosimetry studies, computer-assisted treatment planning, and the design and development of special equipment tailored to developing clinical needs. 1. The improvement of the quality assurance (QA) program for the three Varian accelerators (Clinacs 4, 18 and 20) is a continuing effort. Regular checking of dosimetric and technical set-up aspects of radiation treatment will continue. The M-22 Microtron has been removed. 2. The in-house developed MacIntosh II based treatment planning system is being phased-in for clinical use. 3. Adaptation of the radiation equipment and special supporting equipment and methodology for patient and its implementation is a continuing effort, tailored to the need of ongoing and new clinical research programs.